separate module ConfigFile

1 files changed, 77 insertions, 0 deletions

diff --git a/src/ConfigFile.hs b/src/ConfigFile.hs
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+++ b/src/ConfigFile.hs
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+{-# OPTIONS_GHC -fno-warn-type-defaults #-}
+{-# LANGUAGE ExtendedDefaultRules #-}
+{-# LANGUAGE LambdaCase           #-}
+{-# LANGUAGE NamedFieldPuns       #-}
+{-# LANGUAGE NoImplicitPrelude    #-}
+{-# LANGUAGE OverloadedStrings    #-}
+{-# LANGUAGE RecordWildCards      #-}
+{-# LANGUAGE ScopedTypeVariables  #-}
+
+module ConfigFile where
+import Rebase.Prelude hiding (bool, hash, (<.>))
+
+import Data.Yaml.Combinators
+import Development.Shake            hiding (getEnv)
+import Development.Shake.Command    ()
+import qualified Rebase.Data.Set    as Set
+import Rebase.Data.Text   (pack, unpack)
+import Rebase.Data.Text.Encoding
+import qualified Rebase.Data.Vector as Vector
+{-
+
+Basic idea is to have a fs.yaml that specifies the build procedure. Analogous to
+stack.yaml, it should specify everything (every source) directly or indirectly.
+
+We want to make new images from CoW copies of old ones. We want to build these
+things incrementally, but still end up with something that will be reproducible
+from scratch.
+
+Anyway, what we'll have is a list of packages, which will be unpacked first.
+Then a list of debconf values, which will be applied. Then we will have the rest
+of the other, slower changes to the image (including dpkg --configure -a). Some
+changes can be assumed to produce the same results out of order. Oh right, and
+the zeroeth step is to generate the empty (or just initial) filesystem image.
+The initial filesystem image, if nonempty, is specified by filename (otherwise,
+by size), while the hash of the configuration determines the output filename.
+
+--
+
+'Parent' param should be a config file, not hash. The hash will only be used to
+determine whether we need to build it.
+
+-}
+
+newtype DebconfConfig = DebconfConfig Text deriving (Show, Read, Eq, Ord)
+newtype Package       = Package Text deriving (Show, Read, Eq, Ord)
+data Patch            = Patch deriving (Show, Read)
+
+data BaseImageSpecification
+  = EmptyImageOfBytes Int
+  | ParentImageConfigFile FilePath
+  deriving (Show, Read)
+
+data DiskImageConfig = DiskImageConfig {
+  initialImage   :: BaseImageSpecification
+, packages       :: Set Package
+, debconfConfig  :: Maybe FilePath
+, unpackOnly     :: Bool
+, binaries       :: Vector Text
+, chrootCommands :: Vector Text
+} deriving (Show, Read)
+
+parsePackageName :: Text -> Package
+parsePackageName = Package -- TODO
+
+diskImageConfigParser :: Parser DiskImageConfig
+diskImageConfigParser = object $
+  DiskImageConfig
+  <$> field "parent" ((EmptyImageOfBytes <$> integer) <> (ParentImageConfigFile . unpack <$> string))
+  <*> (Set.fromList . toList . fmap parsePackageName <$> defaultField "packages" Vector.empty (array string))
+  <*> (fmap unpack <$> optField "debconf" string)
+  <*> defaultField "unpack-only" False bool
+  <*> defaultField "binaries" Vector.empty (array string)
+  <*> defaultField "chroot-commands" Vector.empty (array string)
+
+readCfg :: FilePath -> Action DiskImageConfig
+readCfg yaml = either error id . parse diskImageConfigParser . encodeUtf8 . pack <$> readFile' yaml
+